"John is a talented and proven executive who brings a successful track record of leading and operating consumer- and business-focused telecommunications and technology companies," Rene Obermann, CEO of Deutsche Telekom, said in a statement. "As T-Mobile moves forward with its strategic initiatives to improve its market position, including expanding its network coverage and initiating LTE service, John has obviously the right skillset to lead the business into the future."

In the 4G LTE realm, T-Mobile -- the fourth-largest carrier in the U.S. -- is playing catch-up. It should get a boost, though, from Verizon in a spectrum swap that is expected to bring much-needed LTE capabilities to T-Mobile's network.

The 54-year-old Legere formerly was CEO at Global Crossing, a late-1990s telecom up-and-comer that declared bankruptcy about a decade ago. He has also held executive positions at Dell and AT&T.

T-Mobile is one of the few carriers in the U.S. that doesn't offer the Apple iPhone. (The iPhone 5, in case you haven't heard already, will land in consumers' hands on Friday. Check out CNET's full review.) But T-Mobile not without its wiles -- it's got a big campaign going to get iPhone users to switch over to its less-expensive service plans.

Jim Alling has been serving as T-Mobile's interim CEO since June, when Philipp Humm resigned. Alling will return to his position as T-Mobile's chief operating officer.